Warp knit fabrics

ABSTRACT

Warp knit fabrics produced on a machine employing rigid guide needles, sinkers and presser which cooperate with two needle sets mounted on independent needle bars. The needle bars are movable independently in operation with the guide needles and sinkers. The knitting motion preferably requires, in any sequence, at least one alternate and one simultaneous rise and fall movement of each of the two needle bars. A great variety of fabrics may therefore be produced which may have at least some of the stitches arranged in diagonal course lines, may have tack stitches and may have both tight and loose stitches arranged side by side.

United States Patent [191 Brand WARP KNIT FABRICS [76] Inventor: Siegfried F. Brand, RFD 1, Hayes Dr., Yorktown Heights, NY. 10598 [22] Filed: July 12, 1973 [21] App]. No.: 378,758

Related US. Application Data [60] Division of Ser. No. 178,505, Sept. 7, 1971, which is a continuation-in-part of Ser. No. 838,075, July 1, 1969, abandoned.

OTHER PUBLICATIONS Paling, D. F., Warp Knitting Technology, London,

England, 1952, 2nd Ed., Columbine Press, pp. 2, 74, 84.

Paling, Warp Knitting Technology, Columbine, London, England, 1952, 2nd Ed, pp. 107-111.

Primary Examiner-Ronald Feldbaum Attorney, Agent, or FirmRobert J. Blanke [57] ABSTRACT Warp knit fabrics produced on a machine employing rigid guide needles, sinkers and presser which cooperate with two needle sets mounted on independent needle bars. The needle bars are movable independently in operation with the guide needles and sinkers. The knitting motion preferably requires, in any sequence, at least one alternate and one simultaneous rise and fall movement of each of the two needle bars. A great variety of fabrics may therefore be produced which may have at least some of the stitches arranged in diagonal course lines, may have tack stitches and may have both tight and loose stitches arranged side by side.

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WARP KNIT FABRICS BACKGROUND OF THE DISCLOSURE This invention, which is a Divisional Application of co-pending application Ser. No. 178,505, filed Sept. '7, 1971, which is a Continuation-in-Part application of application Ser. No. 838,075, filed July 1, 1969, now abandoned, relates to warp knitting, and more particularly to needle positioning systems in warp knitting.

Since the warp knitting technique provides the fastest means of making yarn into fabric, it has come to be utilized primarily for the mass production of staple textile at the greatest speeds and at the lowest costs. The development of high speed equipment had to be done at the expense of versatility and variety and has created a market for warp-knits, in which a few basic fabrics sell in volume and many novelties in short yardages.

As a consequence there has developed an increasing interest in machines which depart from the standard design and permit the production of new and distinctly different basic fabrics. Even if such devices necessitate decreased speeds and increased costs, they will be fully justifiable and desirable from a standpoint of diversification, so long as the resultant product is unique, cannot be produced by any other practical and more efficient process and the fabric is both attractive and func tional in terms of end use.

A conventional warp knitting machine pulls yarn from two beams on the machine and by stitching joins the yarns of one beam with parallel yarn ends of the other beam. Typically, there are two guide bars extending across the width of the machine and a guide needle on the front bar is provided for each yarn end drawn from one beam. A similar guide needle is provided on a separate guide bar for the corresponding yarn end of the other beam.

In a conventional knitting machine, the stitch needles are mounted in a single needle bar, which is movable upwardly and downwardly with respect to a row of horizontal sinkers extending across the width of the machine.

Knitting machines having split needle bars and rigid guide needles are known, such machines being employed to produce dense or tightly constructed fabrics or to prevent laddering or splitting or to facilitate the production of jacquard patterns through the use of drop pins. Representative of the split needle bar machines of the prior art are German Pat. No. 243,433 issued February, 1912, and German Pat. No. 106,618, issued December, 1899. These prior art split needle machines having been designed to rapidly produce dense fabric have, as in the case of German Pat. No. 106,618 extremely close spacing of the stitch needles. Such an arrangement would ordinarily prevent guide needles from passing between the stitch needles, how

ever, the patented apparatus is permitted to function by employing one guide needle for every pair of stitch needles and adjusting the movement so that the guide needles use the space left unoccupied by the lowered or dormant stitch needles; that is to say, only one split needle bar may be in the raised position.

German Pat. No. 243,433 which has as an objective, the rapid fabrication of dense fabric employs split needle bars which rise in alternation but fall simultaneously in order to speed production. It can therefore be seen that these machines are suitable for the rapid production of dense fabrics, but lack the flexibility necessary for the production of new fabric designs.

The movements of the guide needles, sinkers and v SUMMARY OF THE INVENTION It is the object of this invention to provide method and apparatus for producing novel fabrics by warp knitting.

Another object of this invention is to provide novel warp knitted fabrics.

It is a further object in this invention to provide method and apparatus for readily and conveniently changing stitch patterns in a warp knitting machine.

These objects are accomplished in accordance with a preferred embodiment of the invention by providing two stitch needle bars on a warp knitting machine, with the bars being movable independently by an eccentric device. Needles in both bars face in the same direction, fall into the same line extending transversely of the ma chine and move upwardly and downwardly along parallel axes. The machine is provided with rigid or nondeflectable guide needles, one guide needle being provided for each stitch needle, even though at times, not all of the stitch needles may be threaded, depending on pattern requirements. The total number of stitch needles is the same or less than the corresponding single needle bar on a conventional machine, but variations in the sequence of needles arranged in each of the needle bars provides a variety of stitch patterns that is not possible with conventional machines. The two needle bars are preferably driven by an eccentric device in a manner so that they may be raised both alternately and together in any sequence. When both needle bars are in the raised position, the rigid guide needles may still pass between the stitch needles. The two needle bars preferably have separate warp yarn feed and tension controls. If desired, the eccentric device may be arranged such that tuck stitching is produced. When tuck stitching, both needle bars go up at the same time, but one bar does not come down to the point of cast off, thereby holding individual yarns on the hook of the needle. When the needle with the held yarn is raised again, it will produce a stitch with two yarn ends. A I

tuck stitch may then be made on the other bar to produce a pattern. When tuck stitching, it is preferred that a latch needle be employed.

The basic fabric produced by this invention is a single faced warp knit fabric wherein none of the underlaps cross each other, the fabric having a greatly diminished wale rib and a course line that appears offset rather than straight. The fabric may also have tuck stitches and have both tight and loose stitches knitted side-byside and have at least some of the stitches arranged in diagonal course lines.

DESCRIPTION OF DRAWINGS This preferred embodiment is illustrated in the accompanying drawings in which:

FIG. 1 is a schematic view of the needle bars and as sociated conventional machine structure cooperating with the needle bar structure of this invention;

FIG. 2 is a perspective view of the needle bars;

FIG. 3 is a perspective view of the components shown in FIG. 1, but with the front needle bar lowered:

FIG. 4 is a schematic view of a conventional stitch pattern utilizing a single needle bar;

FIG. 5 is a schematic view of a stitch pattern utilizing the two needle bars of this invention;

FIG. 6 is a schematic view of a stitch pattern utilizing the two needle bars of this invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT A conventional warp knitting machine has two or more beams mounted on the top or back of the machine frame. A sheet of parallel yarns is wound on each beam, each yarn end from one beam passes through the eye of a corresponding guide needle on the guide bar. Referring to FIG. 1, guide bars 2 and 4 are shown schematically. The guide bars are movable in unison about a shaft extending transversely of the machine. This vertical swinging movement of the guide bars is controlled by a cam shaft or other suitable means. The entire guide bar mounting also moves laterally of the machine frame for wrapping the yarn around the needles. This lateral motion is known as a shog.

Rigid guide needles 6 and 8 are secured on the guide bars 2 and 4 respectively. Typically, a plurality of rigid guide needles are formed as a unit and secured on the guide bar. Below the rigid guide needles 6 and 8, sinkers 10 are mounted on a sinker bar 12 that extends across the width of the machine. The sinker bar is movable forwardly and rearwardly. The sinkers 10 are thin metal blades which extend parallel to each other across the width of the machine. Directly above the sinker bar 12, a presser bar 14, which also extends across the width of the machine, is mounted for inward and outward movement. A presser edge 16 extends forwardly from the presser bar 14. I

A pair of needle bars 18 and 20 are provided below the sinker bar 12. Each needle bar has a series of nee dles mounted on the opposed face of the bars. The needles 22 of the rear needle bar 18 are bent forwardly and the needles 24 are bent rearwardly adjacent their base, so that all of the needles are aligned, as shown in FIGS. I and 2. Beard needles are shown in FIGS. 1 and 2,'but, of course, latch needles could also be utilized in accordance with this invention and are preferred when tuck stitching. The needle bars 18 and 20 are supported on arms 26 and 28. The arms 26 and 28 are displaced vertically by cams or other suitable means which are coordinated with the motion of the rigid guide needles, sinker bar and presser bar. The method and structure utilized to control movements of the needle bars 18 and 20 are substantially the same as those currently utilized for controlling conventional single needle bar machines, but the movements of the bars 18 and 20 are separately controlled and are capable of lifting the bars either alternately or together.

As shown in FIG. 3, the needles 22 of the rear needle bar 18 are positioned between pairs of sinkers 10, while the needles 24 of the front needle bar 20 are positioned in the alternate spaces between the sinkers 10. The front needle bar 20 is shown in a lowered position in FIG. 3, so that the needles 24 do not catch the yarn during the underlaps of the guide bars. Thus, the front needle bar 20 remains at rest, while the rear guide bar 18 executes the normal motion, as ifit had the full complement of needles and stitching is carried out on the needles 22 by relative motions of the guide needles 6 and the sinkers 10. At the completion of the stitch on the rear needle bar 18, it is lowered to an inoperative position and the front needle bar 20 is raised into an operative position and moved according to conventional practice for the formation of stitches on the needles 24. The needle bar 20 then returns to its lowered position and the cycle is repeated. Since the needles of the bar which is lowered are not operative for the formation of stitches, the motion of the associated guide needles does not produce a stitch, although a stitch is produced on the needles that are raised.

A typical fabric knitted on a warp knitting machine is shown in FIG. 4. The needle positions are indicated by dots. It can be seen that the yarn loops are formed along straight lines that correspond to the needle positions of the single needle bar of a conventional knitting machine. In FIG. 5, a fabric knitted on apparatus according to this invention is shown. The yarn loops are offset in adjacent courses to produce novel patterns.

In FIG. 6 a fabric knitted on the apparatus of this invention having needle bars set 1 to 1 and two guide bars drawn 1 to I is shown. That is to say, two-set needle bars each knit every second course only with two bars half drawn, covering only the active needles. The fabric is a simple basic stitch 45 bias course line fabric having high flex and recovery.

For simplicity, the needles 22 and 24 are arranged alternately in the rear bar 18 and the front bar 20. Other arrangements of the needles, of course, can be used, although both bars together at any time may contain no more than the total number of needles present in a full-set bar of the particular gauge. For example,

the rear needle bar 18 may have a needle at every other location, as shown in FIG. 3, and the needle bar 20 may have needles at the locations where there are none in the rear needle bar, or the rear needle bar may have 2 needles adjacent to each other, then 2 needle spaces without needles, while the front needle bar has 2 vacant spaces and 2 needles at the locations where there are none in the rear needle bar, or even 3 needles in the rear needle bar and one vacant space, with three vacant spaces in the front needle bar and one needle at the location of the vacant space in the rear needle bar. All of these arrangements are complementary in the sense that total number of needles is no greater than the number of spaces between the sinkers 10. Of course, as another alternative, there may be fewer needles, with vacant spaces left in both bars at appropriate location.

Fabrics made on machines in which the needle bars 18 and 20 have alternate needles 22 and 24 as shown in FIG. 3, offer new and interesting surfaces in which both wale and course lines are less prominent and provide a choice of either better stretch and recovery or greater stability; Thus, many new pattern possibilities are made available.

The two needle bars 18 and 20 are mounted on separate lifting arms 26 and 28, which are driven by separate crankshafts, cams, or eccentric devices in accordance with conventional practice, in such a manner so that they may be raised both alternately and together, in any sequence according to the pattern desired. The lifting mechanisms for the arms 26 and 28 may, for example bev activated by a pattern chain or pattern wheels, similar to the ones now used to control the later'al movement lofthe guide bars, as well as other functions. Such mechanisms provide a great variety in the sequence in which two needle bars may be raised and lowered. Separate yarn feed and tensioning mechanisms and separate knock over adjustments may also be employed so that both tight and loose stitches may be knitted side by side. New fabrics can be produced in accordanee with this invention on either tricot or raschel machines, using heard or latch needles. Moreover, fabrics can be produced in accordance with this invention from very heavy denier yarns which cannot be knitted on a full set single needle bar machine. Such fabrics can be comparatively lightweight fabrics even though produced from relatively heavy denier yarn.

While this invention has been illustrated and described in a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

What is claimed is:

l. A single-faced warp knit fabric, having off-set ap- Front Guide Bar 1-2. lllll. 34, IV-V 4-3. Ill-II Back Guide Bar 4-5, lV-IXL 3-2, 11-], 2-3, Ill-IV Active Needle Bar 1 H l I! I I] where Arabic numberals indicate front-needle-barknitting and Roman numerals indicate back-needle-bar-knitting. 2. The fabric of claim 1 wherein both tight and loose stitches are knitted in successive courses.

3. The fabric of claim 1 wherein at least some of the stitches are tuck stitches. 

1. A single-faced warp knit fabric, having off-set appearing course lines and produced on a warp knitting machine having two guide bars and a split needle bar, the front and back portion of said split needle bar moving alternately, both of said guide bars having one end drawn, and one end missing, said fabric having the following stitch construction:
 2. The fabric of claim 1 wherein both tight and loose stitches are knitted in successive courses.
 3. The fabric of claim 1 wherein at least some of the stitches are tuck stitches. 